The Naturalistic Fallacy
This is an explanation of the naturalistic fallacy, which is trying to draw a conclusion about how things ought to be based solely on information about how things are in fact. For example, some people believe that because the human body currently lives up to an average of 80 years, wanting to live up to age 200 (or 1000 or whatever) is a bad thing, because it's not how nature currently works. I have to disagree.

The 21st century will most likely bring technologies that can radically increase life expectancy, and I would like to live as long as possible without being constrained by whatever our genes currently dictate. It's not that I'm afraid to die, but if I have to choose, I'd much rather live than kick the bucket. A wise man once said: "Choosing to live does not require that I be afraid to die, it only requires that I value life." See this FAQ for more information about life extension.
PS: This was just a rant against some so-called bioethicists who are driving me insane.